[CodeView] Support CodeView subsections in any order.

Previously we would expect certain subsections to appear
in a certain order because some subsections would reference
other subsections, but in practice we need to support
arbitrary orderings since some object file and PDB file
producers generate them this way.  This also paves the
way for supporting Yaml <-> Object File conversion of
CodeView, since Object Files typically have quite a
large number of subsections in their debug info.

Differential Revision: https://reviews.llvm.org/D33807

llvm-svn: 304588

1 files changed, 21 insertions, 7 deletions

diff --git a/llvm/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp b/llvm/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp
index d7a203746a0..c4ff30011a1 100644
--- a/llvm/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp
+++ b/llvm/lib/DebugInfo/PDB/Native/ModuleDebugStream.cpp
@@ -55,9 +55,9 @@ Error ModuleDebugStreamRef::reload() {
   if (auto EC = Reader.readStreamRef(C13LinesSubstream, C13Size))
     return EC;
 
-  BinaryStreamReader LineReader(C13LinesSubstream);
-  if (auto EC =
-          LineReader.readArray(LinesAndChecksums, LineReader.bytesRemaining()))
+  BinaryStreamReader SubsectionsReader(C13LinesSubstream);
+  if (auto EC = SubsectionsReader.readArray(Subsections,
+                                            SubsectionsReader.bytesRemaining()))
     return EC;
 
   uint32_t GlobalRefsSize;
@@ -77,13 +77,27 @@ ModuleDebugStreamRef::symbols(bool *HadError) const {
   return make_range(SymbolsSubstream.begin(HadError), SymbolsSubstream.end());
 }
 
-llvm::iterator_range<ModuleDebugStreamRef::LinesAndChecksumsIterator>
-ModuleDebugStreamRef::linesAndChecksums() const {
-  return make_range(LinesAndChecksums.begin(), LinesAndChecksums.end());
+llvm::iterator_range<ModuleDebugStreamRef::DebugSubsectionIterator>
+ModuleDebugStreamRef::subsections() const {
+  return make_range(Subsections.begin(), Subsections.end());
 }
 
-bool ModuleDebugStreamRef::hasLineInfo() const {
+bool ModuleDebugStreamRef::hasDebugSubsections() const {
   return C13LinesSubstream.getLength() > 0;
 }
 
 Error ModuleDebugStreamRef::commit() { return Error::success(); }
+
+Expected<codeview::DebugChecksumsSubsectionRef>
+ModuleDebugStreamRef::findChecksumsSubsection() const {
+  for (const auto &SS : subsections()) {
+    if (SS.kind() != DebugSubsectionKind::FileChecksums)
+      continue;
+
+    codeview::DebugChecksumsSubsectionRef Result;
+    if (auto EC = Result.initialize(SS.getRecordData()))
+      return std::move(EC);
+    return Result;
+  }
+  return make_error<RawError>(raw_error_code::no_entry);
+}